Beyond the popular stories, Zhongli Quan carries a second and more technical reputation. A considerable body of internal alchemical literature is transmitted under the joint names of Zhongli Quan and Lü Dongbin, the best known being a dialogue in which the elder instructs the younger in the refinement of the vital forces of the body. Whether either man wrote any of it is not a serious question: the texts belong to later periods and use the pair as an authorising frame, in the way traditions regularly do.
That gives him a double life which the atlas records as such. In the temples and on the New Year prints he is a jovial fat man with a fan. In the Daoist canon he is one end of a transmission line for a discipline concerned with the circulation of breath, the sealing of the vital essence and the eventual formation of an immortal embryo, which is described in those texts and is not set out here, since it is a practice transmitted through a teacher.
The Quanzhen school, founded in the twelfth century, placed both men among its patriarchs and thereby joined the popular cult to a monastic order with a real institutional history. The Eight Immortals as a fixed set of eight only settle into their standard membership in the Yuan and Ming periods, on the stage and in fiction, so the group is later than several of its members' individual cults.